-# threadlib.m4 serial 25
+# threadlib.m4 serial 26
dnl Copyright (C) 2005-2019 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
AC_PREREQ([2.60])
-dnl gl_PTHREADLIB
-dnl -------------
-dnl Tests for the libraries needs for using the POSIX threads API.
-dnl Sets the variable LIBPTHREAD to the linker options for use in a Makefile.
-dnl Sets the variable LIBPMULTITHREAD, for programs that really need
-dnl multithread functionality. The difference between LIBPTHREAD and
-dnl LIBPMULTITHREAD is that on platforms supporting weak symbols, typically
-dnl LIBPTHREAD is empty whereas LIBPMULTITHREAD is not.
-dnl Sets the variable LIB_SCHED_YIELD to the linker options needed to use the
-dnl sched_yield() function.
-dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
-dnl multithread-safe programs.
-dnl Defines the C macro HAVE_PTHREAD_API if (at least parts of) the POSIX
-dnl threads API is available.
-
-dnl gl_STDTHREADLIB
-dnl ---------------
-dnl Tests for the libraries needs for using the ISO C threads API.
-dnl Sets the variable LIBSTDTHREAD to the linker options for use in a Makefile.
-dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
-dnl multithread-safe programs.
-dnl Defines the C macro HAVE_THREADS_H if (at least parts of) the ISO C threads
-dnl API is available.
+dnl The general structure of the multithreading modules in gnulib is that we
+dnl have three set of modules:
+dnl
+dnl * POSIX API:
+dnl pthread, which combines
+dnl pthread-h
+dnl pthread-thread
+dnl pthread-once
+dnl pthread-mutex
+dnl pthread-rwlock
+dnl pthread-cond
+dnl pthread-tss
+dnl pthread-spin
+dnl sched_yield
+dnl
+dnl * ISO C API:
+dnl threads, which combines
+dnl threads-h
+dnl thrd
+dnl mtx
+dnl cnd
+dnl tss
+dnl
+dnl * Gnulib API, with an implementation that can be chosen at configure
+dnl time through the option --enable-threads=...
+dnl thread
+dnl lock
+dnl cond
+dnl tls
+dnl yield
+dnl
+dnl They are independent, except for the fact that
+dnl - the implementation of the ISO C API may use the POSIX (or some other
+dnl platform dependent) API,
+dnl - the implementation of the Gnulib API may use the POSIX or ISO C or
+dnl some other platform dependent API, depending on the --enable-threads
+dnl option.
+dnl
+dnl This file contains macros for all of these APIs!
-dnl gl_THREADLIB
-dnl ------------
-dnl Tests for a multithreading library to be used.
-dnl If the configure.ac contains a definition of the gl_THREADLIB_DEFAULT_NO
-dnl (it must be placed before the invocation of gl_THREADLIB_EARLY!), then the
-dnl default is 'no', otherwise it is system dependent. In both cases, the user
-dnl can change the choice through the options --enable-threads=choice or
-dnl --disable-threads.
-dnl Defines at most one of the macros USE_ISOC_THREADS, USE_POSIX_THREADS,
-dnl USE_ISOC_AND_POSIX_THREADS, USE_WINDOWS_THREADS.
-dnl The choice --enable-threads=isoc+posix is available only on platforms that
-dnl have both the ISO C and the POSIX threads APIs. It has the effect of using
-dnl the ISO C API for most things and the POSIX API only for creating and
-dnl controlling threads (because there is no equivalent to pthread_atfork in
-dnl the ISO C API).
-dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use
-dnl in a Makefile (LIBTHREAD for use without libtool, LTLIBTHREAD for use with
-dnl libtool).
-dnl Sets the variables LIBMULTITHREAD and LTLIBMULTITHREAD similarly, for
-dnl programs that really need multithread functionality. The difference
-dnl between LIBTHREAD and LIBMULTITHREAD is that on platforms supporting weak
-dnl symbols, typically LIBTHREAD is empty whereas LIBMULTITHREAD is not.
-dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
-dnl multithread-safe programs.
-dnl Since support for GNU pth was removed, $LTLIBTHREAD and $LIBTHREAD have the
-dnl same value, and similarly $LTLIBMULTITHREAD and $LIBMULTITHREAD have the
-dnl same value. Only system libraries are needed.
+dnl ============================================================================
+dnl Macros for all thread APIs
AC_DEFUN([gl_ANYTHREADLIB_EARLY],
[
fi
])
-AC_DEFUN([gl_THREADLIB_EARLY],
-[
- AC_REQUIRE([gl_THREADLIB_EARLY_BODY])
-])
-
-dnl The guts of gl_THREADLIB_EARLY. Needs to be expanded only once.
-
-AC_DEFUN([gl_THREADLIB_EARLY_BODY],
-[
- dnl Ordering constraints: This macro modifies CPPFLAGS in a way that
- dnl influences the result of the autoconf tests that test for *_unlocked
- dnl declarations, on AIX 5 at least. Therefore it must come early.
- AC_BEFORE([$0], [gl_FUNC_GLIBC_UNLOCKED_IO])dnl
- AC_BEFORE([$0], [gl_ARGP])dnl
-
- AC_REQUIRE([AC_CANONICAL_HOST])
- dnl _GNU_SOURCE is needed for pthread_rwlock_t on glibc systems.
- AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
- dnl Check for multithreading.
- m4_ifdef([gl_THREADLIB_DEFAULT_NO],
- [m4_divert_text([DEFAULTS], [gl_use_threads_default=no])],
- [m4_divert_text([DEFAULTS], [gl_use_threads_default=])])
- m4_divert_text([DEFAULTS], [gl_use_winpthreads_default=])
- AC_ARG_ENABLE([threads],
-AC_HELP_STRING([--enable-threads={isoc|posix|isoc+posix|windows}], [specify multithreading API])m4_ifdef([gl_THREADLIB_DEFAULT_NO], [], [
-AC_HELP_STRING([--disable-threads], [build without multithread safety])]),
- [gl_use_threads=$enableval],
- [if test -n "$gl_use_threads_default"; then
- gl_use_threads="$gl_use_threads_default"
- else
-changequote(,)dnl
- case "$host_os" in
- dnl Disable multithreading by default on OSF/1, because it interferes
- dnl with fork()/exec(): When msgexec is linked with -lpthread, its
- dnl child process gets an endless segmentation fault inside execvp().
- osf*) gl_use_threads=no ;;
- dnl Disable multithreading by default on Cygwin 1.5.x, because it has
- dnl bugs that lead to endless loops or crashes. See
- dnl <https://cygwin.com/ml/cygwin/2009-08/msg00283.html>.
- cygwin*)
- case `uname -r` in
- 1.[0-5].*) gl_use_threads=no ;;
- *) gl_use_threads=yes ;;
- esac
- ;;
- dnl Obey gl_AVOID_WINPTHREAD on mingw.
- mingw*)
- case "$gl_use_winpthreads_default" in
- yes) gl_use_threads=posix ;;
- no) gl_use_threads=windows ;;
- *) gl_use_threads=yes ;;
- esac
- ;;
- *) gl_use_threads=yes ;;
- esac
-changequote([,])dnl
- fi
- ])
- if test "$gl_use_threads" = yes \
- || test "$gl_use_threads" = isoc \
- || test "$gl_use_threads" = posix \
- || test "$gl_use_threads" = isoc+posix; then
- # For using <threads.h> or <pthread.h>:
- gl_ANYTHREADLIB_EARLY
- fi
-])
-
dnl Checks whether the compiler and linker support weak declarations of symbols.
AC_DEFUN([gl_WEAK_SYMBOLS],
esac
])
+dnl ============================================================================
+dnl Macros for the POSIX API
+
+dnl gl_PTHREADLIB
+dnl -------------
+dnl Tests for the libraries needs for using the POSIX threads API.
+dnl Sets the variable LIBPTHREAD to the linker options for use in a Makefile.
+dnl Sets the variable LIBPMULTITHREAD, for programs that really need
+dnl multithread functionality. The difference between LIBPTHREAD and
+dnl LIBPMULTITHREAD is that on platforms supporting weak symbols, typically
+dnl LIBPTHREAD is empty whereas LIBPMULTITHREAD is not.
+dnl Sets the variable LIB_SCHED_YIELD to the linker options needed to use the
+dnl sched_yield() function.
+dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
+dnl multithread-safe programs.
+dnl Defines the C macro HAVE_PTHREAD_API if (at least parts of) the POSIX
+dnl threads API is available.
+
dnl The guts of gl_PTHREADLIB. Needs to be expanded only once.
AC_DEFUN([gl_PTHREADLIB_BODY],
fi
])
+AC_DEFUN([gl_PTHREADLIB],
+[
+ AC_REQUIRE([gl_ANYTHREADLIB_EARLY])
+ gl_PTHREADLIB_BODY
+])
+
+dnl ============================================================================
+dnl Macros for the ISO C API
+
+dnl gl_STDTHREADLIB
+dnl ---------------
+dnl Tests for the libraries needs for using the ISO C threads API.
+dnl Sets the variable LIBSTDTHREAD to the linker options for use in a Makefile.
+dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
+dnl multithread-safe programs.
+dnl Defines the C macro HAVE_THREADS_H if (at least parts of) the ISO C threads
+dnl API is available.
+
dnl The guts of gl_STDTHREADLIB. Needs to be expanded only once.
AC_DEFUN([gl_STDTHREADLIB_BODY],
fi
])
+AC_DEFUN([gl_STDTHREADLIB],
+[
+ AC_REQUIRE([gl_ANYTHREADLIB_EARLY])
+ gl_STDTHREADLIB_BODY
+])
+
+dnl ============================================================================
+dnl Macros for the Gnulib API
+
+dnl gl_THREADLIB
+dnl ------------
+dnl Tests for a multithreading library to be used.
+dnl If the configure.ac contains a definition of the gl_THREADLIB_DEFAULT_NO
+dnl (it must be placed before the invocation of gl_THREADLIB_EARLY!), then the
+dnl default is 'no', otherwise it is system dependent. In both cases, the user
+dnl can change the choice through the options --enable-threads=choice or
+dnl --disable-threads.
+dnl Defines at most one of the macros USE_ISOC_THREADS, USE_POSIX_THREADS,
+dnl USE_ISOC_AND_POSIX_THREADS, USE_WINDOWS_THREADS.
+dnl The choice --enable-threads=isoc+posix is available only on platforms that
+dnl have both the ISO C and the POSIX threads APIs. It has the effect of using
+dnl the ISO C API for most things and the POSIX API only for creating and
+dnl controlling threads (because there is no equivalent to pthread_atfork in
+dnl the ISO C API).
+dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use
+dnl in a Makefile (LIBTHREAD for use without libtool, LTLIBTHREAD for use with
+dnl libtool).
+dnl Sets the variables LIBMULTITHREAD and LTLIBMULTITHREAD similarly, for
+dnl programs that really need multithread functionality. The difference
+dnl between LIBTHREAD and LIBMULTITHREAD is that on platforms supporting weak
+dnl symbols, typically LIBTHREAD is empty whereas LIBMULTITHREAD is not.
+dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
+dnl multithread-safe programs.
+dnl Since support for GNU pth was removed, $LTLIBTHREAD and $LIBTHREAD have the
+dnl same value, and similarly $LTLIBMULTITHREAD and $LIBMULTITHREAD have the
+dnl same value. Only system libraries are needed.
+
+AC_DEFUN([gl_THREADLIB_EARLY],
+[
+ AC_REQUIRE([gl_THREADLIB_EARLY_BODY])
+])
+
+dnl The guts of gl_THREADLIB_EARLY. Needs to be expanded only once.
+
+AC_DEFUN([gl_THREADLIB_EARLY_BODY],
+[
+ dnl Ordering constraints: This macro modifies CPPFLAGS in a way that
+ dnl influences the result of the autoconf tests that test for *_unlocked
+ dnl declarations, on AIX 5 at least. Therefore it must come early.
+ AC_BEFORE([$0], [gl_FUNC_GLIBC_UNLOCKED_IO])dnl
+ AC_BEFORE([$0], [gl_ARGP])dnl
+
+ AC_REQUIRE([AC_CANONICAL_HOST])
+ dnl _GNU_SOURCE is needed for pthread_rwlock_t on glibc systems.
+ AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+ dnl Check for multithreading.
+ m4_ifdef([gl_THREADLIB_DEFAULT_NO],
+ [m4_divert_text([DEFAULTS], [gl_use_threads_default=no])],
+ [m4_divert_text([DEFAULTS], [gl_use_threads_default=])])
+ m4_divert_text([DEFAULTS], [gl_use_winpthreads_default=])
+ AC_ARG_ENABLE([threads],
+AC_HELP_STRING([--enable-threads={isoc|posix|isoc+posix|windows}], [specify multithreading API])m4_ifdef([gl_THREADLIB_DEFAULT_NO], [], [
+AC_HELP_STRING([--disable-threads], [build without multithread safety])]),
+ [gl_use_threads=$enableval],
+ [if test -n "$gl_use_threads_default"; then
+ gl_use_threads="$gl_use_threads_default"
+ else
+changequote(,)dnl
+ case "$host_os" in
+ dnl Disable multithreading by default on OSF/1, because it interferes
+ dnl with fork()/exec(): When msgexec is linked with -lpthread, its
+ dnl child process gets an endless segmentation fault inside execvp().
+ osf*) gl_use_threads=no ;;
+ dnl Disable multithreading by default on Cygwin 1.5.x, because it has
+ dnl bugs that lead to endless loops or crashes. See
+ dnl <https://cygwin.com/ml/cygwin/2009-08/msg00283.html>.
+ cygwin*)
+ case `uname -r` in
+ 1.[0-5].*) gl_use_threads=no ;;
+ *) gl_use_threads=yes ;;
+ esac
+ ;;
+ dnl Obey gl_AVOID_WINPTHREAD on mingw.
+ mingw*)
+ case "$gl_use_winpthreads_default" in
+ yes) gl_use_threads=posix ;;
+ no) gl_use_threads=windows ;;
+ *) gl_use_threads=yes ;;
+ esac
+ ;;
+ *) gl_use_threads=yes ;;
+ esac
+changequote([,])dnl
+ fi
+ ])
+ if test "$gl_use_threads" = yes \
+ || test "$gl_use_threads" = isoc \
+ || test "$gl_use_threads" = posix \
+ || test "$gl_use_threads" = isoc+posix; then
+ # For using <threads.h> or <pthread.h>:
+ gl_ANYTHREADLIB_EARLY
+ fi
+])
+
dnl The guts of gl_THREADLIB. Needs to be expanded only once.
AC_DEFUN([gl_THREADLIB_BODY],
AC_SUBST([LTLIBMULTITHREAD])
])
-AC_DEFUN([gl_PTHREADLIB],
-[
- AC_REQUIRE([gl_ANYTHREADLIB_EARLY])
- gl_PTHREADLIB_BODY
-])
-
-AC_DEFUN([gl_STDTHREADLIB],
-[
- AC_REQUIRE([gl_ANYTHREADLIB_EARLY])
- gl_STDTHREADLIB_BODY
-])
-
AC_DEFUN([gl_THREADLIB],
[
AC_REQUIRE([gl_THREADLIB_EARLY])
])
+dnl ============================================================================
+
+
dnl Survey of platforms:
dnl
dnl Platform Available Compiler Supports test-lock